Synthesis and characterization of new magnetic materials Eu_0.5La_0.5Fe₂Sb₂ and EuFe_1.2Ni_0.2Sb₂

The whole work is dedicated to the synthesis and the study of physical properties of the new magnetic materials such as Eu_0.5 La_0.5Fe₂ Sb₂ and EuFe_1.8Ni_0.2Sb₂. These materials are comparatively new class of magnetic materials. Although so many papers have been reported on these classes of related materials, but our present study mainly focus on the Fe sites. The controlling of chemical pressure leads to suppress the magnetic property of Fe ion and finally to retrieve the superconductivity from these compounds. In order to get new superconducting materials with higher T_c, here we represented Eu_0.5La_0.5Fe₂Sb₂ and EuFe_1.8Ni_0.2Sb₂ synthesized by solid state reaction method. Phase identification, crystallite size and morphology of polycrystalline sample were investigated through XRD powder diffraction pattern and SEM micrographs. The variable temperature and field dependent magnetic studies are done by using Quantum Design PPMS connected with VSM. Unfortunately, we were not able to control the magnetic property of iron due to the lack of synthesis facilities, to avoid the oxygen deficient and also difficulty to control the volatility of rare earth Sb atoms during reaction. The samples of Eu_0.5La_0.5Fe₂Sb₂ and EuFe_1.8Ni_0.2Sb₂ show strong ferromagnetic order at 115 K and 125 K were found by ^χvs T measurement. Isothermal magnetization measurements reveal that samples exhibit semi hard magnetic behavior at low temperature and these are mainly used for various commercial applications. To study the superconductivity, electrical and antistrophic magnetic behavior of these new compounds, single crystals would be favorable. (author)